Synthesis of Annulated Pyrroles: Condensation of Aldose Sugars, Arylamines, and 1,3-Diones Using TBAB

Abstract

Readily available tetrabutylammonium bromide (TBAB, 10 mol%), in the molten state, efficiently catalyzes the reaction of a variety of in situ generated enamines, from arylamines and 1,3-ketones, with aldose sugars under solvent-free conditions. The reaction proceeds rapidly and affords the corresponding protected annulated pyrrole derivatives in good to high yields (55-78%) after acetylation. The present methodology offers advantages such as excellent yields, a simple procedure, shorter reaction times, and milder conditions.

Key words

aldose sugars - 1,3-diones - tetrabutylammonium bromide - one-pot synthesis - shorter reaction times

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